Refrigerant distributor for cooling units



Jan. 23, 1941. w A, SPQFF'QRD. 2,229,940

REFRIGERANT DISTRIBUTOR FOR COOLING UNITS Filed Dec. 28, 1939 2 Sheets-Sheet 1 Fig. I.

Irv/enter: Warren A. Spofford b z/a y His Attorney.

Jan. 28, 1941. A SPQFFQRD 2,229,940

REFRI GERANT DISTRIBUTOR FOR COOLING UNITS Filed Dec. 28, 1939 2 Sheets-Sheet 2 F126. F197 r Inven tor: War ren A. Spofford,

by His Attorney plied to all of the evaporating elements.

Watented Jan. 28, 1941 UNITED STATES PATENT OFFICE ING UNITS Warren A. Spofford, Glen Ridge, N. J., assignor to General Electric Company, a corporation of New York Application December 28, 1939, Serial No. 311L429? 6 Claims.

My invention relates to cooling units of the type having a plurality of evaporator elements supplied with refrigerant from a single expan sion valve, and particularly to refrigerant distributing arrangements for such units.

Cooling units are frequently constructed with a plurality of separate evaporating elements such as sinuous tubes arranged in banks and connected to be supplied with refrigerant through a single expansion device such as a thermostatic expansion valve. Simple inlet manifolds whereby all the tubes are connected to receive refrigerant from a single conduit have been found to be unsatisfactory in many installations due to uneven distribution of liquid and gaseous refrigerant to the several evaporating elements. In order that the cooling unit may operate efiiciently, each element should carry the same proportion of the load and this distribution of the load can be accomplished satisfactorily when substantially equal quantities of a uniform mixture of gaseous and liquid refrigerant are sup- Accordingly, it is an object of my invention to provide a refrigerant distributor for the evaporator of a refrigerating system including an improved arrangement for providing uniform distribution of liquid and gaseous refrigerant to a plurality of evaporating elements supplied from a single expansion valve.

Further objects and advantages of my invention will become apparent as the following description proceeds, and the features of novelty which characterize my invention will be pointed out with particularity in the claims annexed to and forming a part of this specification.

For a better understanding of my invention, reference may be had to thej accompanying drawings, in which Fig. l is adiagrammatic view of a cooling unit for an air conditioning system provided with a refrigerant distributing device embodying my invention; Fig. 2 is an enlarged sectional view of the distributing device shown in Fig. 1; Fig. 3 is an enlarged end view of the device shown in Fig. 1; Figs. 4 and 5 are sectional views similar to Fig. 2 showing modified forms of my invention; Fig. 6 is a side elevation partly in section showing a water chiller provided with a refrigerant distributing device embodying my invention; .Fig. 7 is an end elevation view of the chiller shown in Fig. 6; Fig. 8 is an enlarged sectional view of the refrigerant distributing header of the water chiller shown in Fig. 6; and 9 is a horizontal sectional view of the header shown in Fig. 8 with the outer cover removed.

The refrigerant distributing arrangement as shown on the drawings comprises generally a casing divided into tWo chambers communicating at their upper portions. Gaseous and liquid refrigerant flowing from the expansion valve enters one of the chambers preferably near the bottom and flows therefrom into the upper portion of the other chamber. A plurality of outlets communicate with the other chamber and are connected to distribute refrigerant to a plurality of evaporating elements of the cooling unit of a refrigerating machine, and in order to provide even distribution of liquid and gaseous reirigerant to the several outlets, a stack or mass of readily permeable material is arranged in the second chamber adjacent a plurality of the outlets.

Referring now to the drawings, in Fig. l I have shown a cooling unit it arranged in a duct IHI so that air to be cooled may be circulated thereover. The cooling unit comprises a plurality of evaporating elements in the form of sinuous coils it extending baclr: and forth across the duct ill in the path of the air. Vaporized refrigerant is withdrawn from the evaporating elements it by operation of a compressor it, the several elements it communicating with a manifold Ml which is connected to the compressor by a suction line it. The compressor it is driven by a motor it and compresses the gaseous refrigerant, the hot compressed refrigerant being delivered through a discharge line if to a condenser it? which is cooled by air circulated by a motor driven fan ill. The hot compressed refrigerant is cooled and liquefied in the condenser and flows to a liquid receiver it and is returned to the evaporator through a liquidline it under control of a thermostatic expansion valve it having a thermal element til secured to the suction manifold Hi. In order to provide even distribution of liquid refrigerant and any gaseous refrigerant formed by evaporation of liquid at the expansion valve M, ii provide a distributor 2d arranged to supply equal quantities of refrigerant through vertically spacedv outlet connections 2% to the several evaporating elements it of the cooling unit it.

As shown in Figs. 2 and 3, the distributor it comprises a rectangular casing having a partition it dividing it into two compartments 2i and it lncommunication through a passage 29 at the upper end of the partition. The several outlet connections it are arranged preferably in vertical alinement. For purposes of illustration, the casing has been shown as thin and fiat with a single vertical row of outlets; obviously, however, a casing having a plurality of vertical rows may be employed if a greater number of outlets is desired. During the operation of the refrigerating system, a mixture of liquid and gaseous refrigerant is discharged from the thermostatic expansion valve 22 through a connection 2|a and enters the bottom of the chamber 21 where it is directed against the partition 26 which acts as a baflle breaking the force of the fluid stream and directing a mixture of liquid and gaseous refrigerant upwardly and through the communicating opening 29. The liquid and gaseous refrigerant thus enters the chamber 28 where there is a tendency for the major portion of the liquid to enter the upper and lower ones of the outlets 25, relatively small amounts entering the central outlets. I have found that by providing a mass of readily permeable material 30 in the chamber 28 covering a plurality of the outlets 25 a substantially even distribution of the quantities of liquid and gaseous refrigerant to all of the outlets 25 may be obtained. Permeable material 36 may be formed by a stack of screens or similar elements and I have found that very satisfactory results are obtained when the material 30 fills the chamber 28 to a level substantially three-quarters the distance between the top and bottom outlets. The most desirable level for the -mass of permeable material may readily be determined by trial in any particular installation for the required range of loads on the refrigerating machine. In order that the quantity of screen-like material may be adjusted, I construct the casing so that one wall thereof may be removed. In the embodiment illustrated, the top wall 3| may be removed by first removing a plurality of bolts 32. During the operation of the refrigerating system, the mass of readily permeable material 38 prevents the falling of a major portion of liquid refrigerant to the bottom of the chamber 28 and there results an even distribution of both liquid and gaseous refrigerant through all of the conduits 25. Under most conditions of operation, it will be found that one or more of the upper outlets will not be covered by the screening material 30.

Under some conditions of operation, I have found that the evenness of the distribution may be more easily obtained by slanting the planes of the screens in the stack forming the mass of material 30 downwardly toward the outlets 25 as indicated at 33 in Fig. 4. In Fig. 5, I have illustrated the distributor shown in Fig. 2 provided with a mass of readily permeable material 34 comprising metal turnings or the like.

During the operation of the refrigerating system illustrated in Fig, 1, the thermostatic expansion valve will supply refrigerant to the cooling unit I8 at a rate sufilcient to insure a predetermined number of degrees of superheat of the vaporized refrigerant withdrawn through the manifold Hi, this control being effective in the usual manner in accordance with the pressure at the outlet of the expansion valve and the temperature as indicated by the thermal element 23. The distributor 24 will insure the even distribution of a mixture of liquid and gaseous refrigerant to all of the evaporator elements l2 and the cooling load will, therefore-be carried equally by the several elements and will be distributed evenly over the cross-section of the duct Referring again to the drawings, in Figs. 6 and 7 I have shown a water chiller of the type employed for supplying chilled water to the cooling coils of air conditioning systems. The chiller comprises a cylinder casing 35 having end plates 36 and 31 bolted to suitable flanges 38 and 39, respectively, and closing the ends of the casing. Water to be chilled is admitted to the casin through an inlet connection 40 at the bottom thereof and is discharged therefrom through an outlet connection 4|. A plurality of baflies 42 are provided to direct the water in a zigzag course through the chiller over the surface of a plurality of U-shaped refrigerant conduits 43 passing through the bafiles 42. The open ends of the conduits 43 are secured in the end plate 31. An inlet header 44 is provided for supplying refrigerant to the tubes 43 and an outlet header 45 is provided to collect the vaporized refrigerant and 1 remove it from the chiller through an outlet conduit or suction line 46. The pipes 43 where they enter the headers 44 and 45 are arranged in a plurality of horizontal rows, corresponding ones of the tubes in each horizontal row being arranged in substantially upright alinement, successive tubes being displaced the width of a tube so that the U-shaped turns may be inserted in the cooler without the necessity of bending them around one another as would be the case were the tubes arranged in exact vertical alinement. Refrigerant is supplied to the header 44 from a liquid line 41 through a thermostatic expansion valve 48 having a control bulb or thermal element 49 immersed in the gaseous refrigerant withdrawn from the header 45, a T-connection being provided to accommodate the thermal element. The construction and arrangement of the header 44 is similar to that of the header shown in Figs. 1 to 5 inclusive. The header 44 is closed by an end plate 5| suitably bolted to the header. The end plate 5| is provided with an inlet connection for receiving refrigerant from the valve'48. An upright baille plate 53 is arranged within the header in a manner similar to the header 26 shown in Fig. 2, and a stack of screens or similar material 54 is arranged in the left-hand chamber formed by the bafile plate within the header, the arrangement of the screens being similar to that shown in Fig. 4. I have found it desirable in some cases to provide anarrangement for insuring uniform distribution of the mixture of liquid and gaseous refrigerant horizontally of the header. A screen-like bafile or similar element 55 arranged in the passage of horizontally elongated cross-section formed at the top of the baflle 53 between the two chambers of the header has been found satisfactory for this purpose, the liquid refrigerant tending t be distributed along the length of the scree As a further aid to the horizontal distribution of refrigerant and breaking up of the velocity effects at the inlet 52, I may provide a horizontally arranged foraminous plate 56 provided with a large number of holes 51, as clearly shown in Fig. 9 which is a view of the header with the cover plate 5| removed. The plate 56 may be secured in place in any suitable manner as by spot welding.

During the operation of the water chiller, water is circulated through the chiller and around the bafiles from the inlet 40 to the outlet 4| and refrigerant flows through the tubes 43 under control of the thermostatic expansion valve 48. The inrush of the refrigerant to the header 44 is broken up by the bailie 56 and the mixture of liquid and gaseous refrigerant is, furthermore, supplied uniformly over the length of the passageway 53 by the action of the screen 55. Refrigerant entering the left-hand chamber of the header as shown in Fig. 8, is distributed evenly to the several tubes 43 in the same manner as described in connection with the tubes 25 in Figs. 1 to 5 inclusive. By this arrangement, each of the U-shaped tubes 43 carries substantially the same load and the water is chilled effectively with efficient use of the refrigerant in all the tubes.

From the foregoing, it is apparent that I have provided a simple and easily constructed arrangement for distributing a mixture of liquid and gaseous refrigerant uniformly to a plurality of evaporators. The arrangement is of rugged construction and requires no moving parts and may be adjusted to meet varying conditions of operation.

While I have disclosed a particular embodiment of my invention in connection with a cooling unit for air conditioning systems, other applications will occur to those skilled in the art.

I do not, therefore, desire my invention to be limited to the construction shown and described, and I intend in the appended claims to cover all modifications within the spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. A distributor for supplying refrigerant to a plurality of evaporating elements of a refrigerating system comprising a casing providing a chamber, an inlet for admitting refrigerant to the upper portion of said chamber, a plurality of vertically spaced outlets for conducting refrigerant from said chamber, and a mass of readily permeable screen-like material filling said chamber to a level at approximately three-fourths of the distance between the top and bottom ones of said outlets for producing a substantially uniform flow of a mixture of liquid and gaseous refrigerant from said casing through all of said outlets.

2. A refrigerant distributor for supplying refrigerant to a plurality of evaporating elements of a refrigerating system comprising a casing having therein two chambers in communication near their upper portions, an inlet for admitting refrigerant to one of said chambers, a plurality of vertically spaced outlets for conducting refrigerant from the other of said chambers, and a mass of readily permeable material in said other chamber adjacent a plurality of said outlets for producing a substantially uniform flow of a mixture of liquid and gaseous refrigerant from said casing through all of said outlets.

3. A distributor for supplying refrigerantto a plurality of evaporating elements of a refrigerating system comprising a casing providing a chamber, an inlet for admitting refrigerantto the interior of said casing, a deflecting baffle within said casing directly opposite said inlet and arranged to direct refrigerant upwardly and thence downwardly into said chamber, a plurality of vertically spaced outlets for conducting refrigerant from said chamber, and a mass of readily permeable material in said chamber adjacent a plurality of said outlets for producing a substantially uniform flow of a mixture of liquid and gaseous refrigerant from said casing through all of said outlets.

4. A distributor for supplying refrigerant to a plurality of evaporating elements of a refrigerating system comprising a casing providing a chamber, an inlet for admitting liquid and gaseous refrigerant to the upper portion of said chamber, a plurality of outlets arranged vertically in substantial alinement for conducting refrigerant from said chamber and a stack of screens in said chamber filling said chamber to a level covering a plurality of said outlets for producing a substantially uniform flow of a mixture of liquid and gaseous refrigerant from said chamber through all of said outlets, the planes of the screens in said stack sloping downwardly toward said outlets.

5. A refrigerant distributor for supplying refrigerant to a plurality of evaporating elements of a refrigerating system comprising a casing having therein two chambers and a passage of horizontally elongated cross-section providing communication near their upper portions, an inlet for admitting refrigerant to one of said chambers, a plurality of outlets arranged in a plurality of horizontal rows for conducting refrigerant from the other of said chambers, corresponding ones of said outlets in said horizontal rows being arranged in substantially upright alinement, a screen-like baflie arranged in said passage for facilitating substantially uniform horizontal distribution of liquid and gaseous refrigerant along said passage, and a mass of readily permeable material in said other chamber adjacent a plurality of said outlets for producing a substantially uniform flow of a mixture ofiiquid and gaseous refrigerant from said casing through all of said outlets.

6. ,A refrigerant distributor for supplying refrigerant to a plurality of evaporating elements of a refrigerating system comprising a casing having therein two chambers and a passage of horizontally elongated cross-section providing communication near their upper portions, an inlet for admitting refrigerant to one of said chambers, a plurality of outlets arranged in a plurality of horizontal rows for conducting refrigerant from the other of said chambers, corresponding ones of said outlets in said horizontal rows being arranged in substantially upright alinement, a. foraminous plate arranged in said one chamber between said inlet and said e for facilitating even distribution of liquid and gaseous refrigerant along said passage, and-a mass of readily permeable material in said other chamber adjacent a plurality of said outlets for producing a substantially uniform flow of a mixture of liquid and gaseous refrigerant from said casing through all of said outlets.

WARREN A. SPOFFORD. 

